Sen. John McCain said on Tuesday he can "personally vouch" there was nothing disqualifying in the 23 years' worth of tax returns that Mitt Romney submitted to his team in 2008, when he was vetted for a vice presidential spot.

"Everything was fine," McCain told reporters on Capitol Hill. "I can personally vouch for the fact that there was nothing in his tax returns that would in any way be disqualifying for him to be a candidate."

When pressed about whether Romney might be shielding his returns because he paid no taxes, McCain refused to discuss such specifics.

"Please, I am not going to get into that kind of conversation," he said. "All I can tell you, and I can tell you again, is there was nothing disqualifying in his tax returns. And that is a fact."

Romney has released his 2010 tax return and said he will release his 2011 return as well.

McCain, whose campaign reviewed 23 years' worth of Romney tax returns in 2008, said that the former Massachusetts governor should not give way to increasing pressure. McCain's comments echoed those made by his former campaign manager, Steve Schmidt, who told The Huffington Post that Romney's taxes did not play a role in McCain's passing him over for the vice president spot.

"So if your opponent makes a big deal out of some issue, then you're supposed to do something that no one else has done?" McCain asked. "Like if you're married to a very wealthy billionaire, should you have been revealing her tax returns?"